Nonwoven fabric with high CD elongation and method of making same

ABSTRACT

A nonwoven fabric from spun fibers wherein the density of the spun fibers in the fabric varies between strips of relatively high density and strips of relatively low density. The strips extend along the length of the fabric in the machine direction in an alternating pattern, with the high density strips separated from each other by low density strips. The alternating high density and low density strips provide the fabric with a higher percent elongation in the cross direction than in the machine direction. The alternating pattern is achieved through use of a pattern screen defining a plurality of elongated air permeable regions separated by elongated substantially or relatively air impermeable regions, the elongated regions extending in the machine direction in an alternating pattern, with the air permeable regions separated from each other by the substantially or relatively air impermeable regions.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This is a continuation-in-part of U.S. patent application Ser.No. 09/460,659, filed Dec. 13, 1999, itself a continuation-in-part ofU.S. patent application Ser. No. 09/373,826, filed Aug. 13, 1999.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a nonwoven having a filamentdensity pattern yielding low tensile strength and high percentelongation in a first direction (e.g., CD) and high tensile strength andlow percent elongation in a second direction (e.g., MD), and a method ofmaking such a nonwoven.

[0003] Spunbond nonwoven fabrics are made of continuous strands orfilaments that are laid down on a moving conveyor belt in a randomizeddistribution. In a typical spunbond process, resin pellets are processedunder heat to a melt and then fed through a spinnerette to createhundreds of thin filaments or threads. Jets of fluid (e.g., a gas suchas air) causes the threads to be elongated, and the threads are thenblown or carried onto a moving web where they are laid down and suckedagainst the web in a random pattern to create a fabric. The filamentdensity of the fabric is typically fairly uniform and symmetricallyextending in both the machine direction (MD) and the cross direction(CD) (at least this is the goal). The fabric then passes through abonding station. Bonding is necessary because the filaments or threadsare not woven together.

[0004] Other nonwoven fabrics include fabrics made from staple fibers,meltblown fibers, carded fibers and short cut fibers. As used herein theterms “spun fibers” and “fibers” include the spun filaments describedabove as well as staple fibers, meltblown fibers, carded fibers andshort cut fibers.

[0005] A non-uniform and non-symmetrical fiber density pattern couldresult in a fabric with an expected elongation in one direction (e.g.,MD), but an unexpected increased elongation in the other direction(e.g., CD). This is desired in situations where minimal elongation isrequired in the machine direction and yet high elongation is required inthe cross direction. For example, any elongation in the machinedirection will disrupt the converting machines that are used to makediapers, while substantial elongation in the cross direction is desiredto give each individual diaper some give around the wearer's waist.

[0006] Accordingly, it is an object of the present invention to providea nonwoven fabric having a non-uniform fiber density pattern and amethod of making such fabric.

[0007] Another object of the present invention is to provide a nonwovenfabric and method of making same wherein in one embodiment the fabric ishighly extensible in a first direction (typically the CD) as compared toa second direction (typically the MD).

[0008] Another object of the present invention is to provide a nonwovenfabric and method of making same wherein in one embodiment the fibers ofthe fabric are oriented more in the MD than in the CD thereby providinghigher tensile strength in the MD than in the CD.

[0009] Another object is to provide such a method and fabric wherein inone embodiment the nonwoven fabric has low tensile strength and highpercent elongation in the first direction (typically the CD), and hightensile strength and low percent elongation in the second direction(typically the MD).

[0010] It is a further object to provide such a method and fabricwherein in one embodiment the density of the fibers in the fabric variesbetween strips of relatively high density and strips of relatively lowdensity, the strips extending substantially continuously along thelength of the fabric in the machine direction in an alternating pattern.

[0011] It is a still further object of the invention to provide such afabric wherein in one embodiment less fibers are bonded together in thestrips of relatively low fiber density than in the strips of relativelyhigh fiber density.

[0012] It is a still further object of the invention to provide such afabric which in one embodiment provides increase liquid wicking in thestrips of relatively high fiber density and increased liquidstrike-through in the strips of relatively lower fiber density.

[0013] It is a still further object of the invention to provide such afabric which in one embodiment has a shrinkage differential between thestrips of relatively high fiber density and the strips of relativelylower fiber density when the fabric is exposed to heat, with greatershrinkage in the strips of relatively high fiber density.

[0014] It is also an object of the present invention to provide such amethod which in one embodiment is simple and economical to use andmaintain.

[0015] It is an object of the present invention to provide an improvedprocess for the method of manufacturing a nonwoven according to thepresent invention and an improved nonwoven wherein, in one embodiment,the design of the fluid impermeable and fluid permeable regions appearsregular and a biasing thereof in one direction is difficult to discernby the ordinary viewer.

[0016] It is another object to provide such an improved process andnonwoven wherein, in one embodiment, the fabric defines both fluid flowhighways of low thickness and parallel fluid flow barriers of highthickness, thereby to encourage fluid flow in the MD and retard fluidflow in the CD.

[0017] It is a further object to provide such an improved process andnonwoven wherein, in one embodiment, a composite fabric includes anonwoven according to the present invention and an elastic film thereon,the composite exhibiting a reduced propensity for breaking of thebonding points upon stretching in the CD.

[0018] It is a still further object of the present invention to providesuch an improved process wherein, in one embodiment, jets of a liquidfluid (rather than a gaseous fluid) impinge on the spun fibers in orderto enhance redirection of the spun fibers.

SUMMARY OF THE INVENTION

[0019] It has now been found that the above and related objects of thepresent invention are obtained in a nonwoven fabric formed from spunfibers wherein the density of the fabric varies between strips ofrelatively high density and strips of relatively low density, the stripsextending along the length of the fabric in the machine direction in analternating pattern. The high density strips are separated from eachother by low density strips, the alternating high density and lowdensity strips providing the fabric with a higher percent elongation inthe cross direction than in the machine direction. The method comprisesthe steps of forming a flowing stream of spun fibers and moving an air(or like fluid) permeable member over a suction box and across the pathof the fiber stream to intercept and collect the fibers on one face ofthe air permeable member and to bond the collected fibers together toform a nonwoven fabric. A pattern screen is provided, the pattern screendefining a plurality of elongated air (or like fluid) permeable regionsseparated by elongated relatively air (or like fluid) impermeableregions, the elongated regions extending in the machine direction in analternating pattern, with the air permeable regions separated from eachother by the relatively air impermeable regions. The pattern screen ispositioned in relation to the air permeable member and the suction boxto cause the fibers to be collected on the one face of the air permeablemember so as to form a fabric having a density that varies betweenstrips of relatively high density and strips of relatively low density.The strips extend along the length of the fabric in the machinedirection in an alternating pattern, with the high density stripsseparated from each other by low density strips, the alternating highdensity and low density strips providing the fabric with a higherpercent elongation in the cross direction than in the machine direction.The collected fibers are then separated from the air pervious member.

[0020] In a preferred embodiment, the relatively air impermeable regionsdisrupt the air flow directly above the air pervious member, and thepattern screen comprises longitudinally extending and transverselyspaced air impermeable baffle bars. The pattern screen is preferablybelow the suction box cover, in the plane of the suction box cover,between the suction box cover and the air permeable member, or part ofthe air permeable member (i.e., on the top of, on the bottom of orwithin the air permeable member).

[0021] The present invention also encompasses a method of making anonwoven fabric embodying spun fibers deposited in a patterned formationproviding a higher percent elongation in CD than in MD. The methodcomprises the steps of forming a flowing stream of spun fibers and air(or like fluid), and moving an air pervious member over a suction boxcover and across the path of the fiber stream to intercept and collectthe fibers on one face of the air pervious member. A pattern screen isdisposed as the suction box cover, thereby to cause the fibers to becollected on the one face of the air pervious member in a patterndetermined by the pattern on the pattern screen and to bond thecollected fibers together to form a nonwoven fabric. The pattern definesan air pervious area/air impervious area ratio which is greater in MDthan in CD, thereby to provide a fabric with a higher percent elongationin CD than in MD. The collected fibers are then separated from the airpervious member.

[0022] In a preferred embodiment, the pattern screen compriseslongitudinally extending and transversely spaced substantially airimpermeable baffle bars thereby to impose the pattern of the baffle barson the suction exerted on the filaments by the suction box. Theapertures of the air pervious member define a regular non-orientedpattern.

[0023] The present invention further encompasses an improved method ofmaking the nonwoven fabric using a pattern screen wherein the elongatedfluid permeable regions are configured and dimensioned as rhomboidselongated in the MD, or wherein a liquid (such as water) redirects thespun fibers in the formed web (with removal of the liquid beingperformed by a liquid discharge box rather than a suction box), orwherein the thickness of the fabric varies between strips of relativelyhigh thickness (which act as speed bumps to fluid flow in the CD) andstrips of relatively low thickness (which act as highways for fluid flowin the MD), or wherein an elastic polymeric film is coated (preferablycast coated) onto the fabric in the MD and the composite of thecollected fibers and the elastic film is separated from the fluidpermeable member. Preferably the fabric has an MD/CD density ratio of1.1-10.0 (preferably 1.5-3.0) to 1.0. Preferably the thickness of thelow thickness strips is only 10-90% (preferably 25-75%) of the thicknessof the high thickness strips.

BRIEF DESCRIPTION OF THE DRAWING

[0024] The above and related objects, features and advantages of thepresent invention will be more fully understood by reference to thefollowing detailed description of the presently preferred, albeitillustrative, embodiments of the present invention when taken inconjunction with the accompanying drawing wherein:

[0025]FIG. 1 is a fragmentary schematic illustrating a spunbondingprocess;

[0026]FIGS. 2A, 2B and 2C are fragmentary top plan views of an airpermeable member (such as a conveyor) for use in the present invention;

[0027]FIG. 3 is a fragmentary isometric view of a suction box providingair impermeable members above the suction box and above the conveyorbelt;

[0028]FIG. 4 is a fragmentary isometric view of a suction box providingair impermeable members within the suction box and below the conveyorbelt;

[0029]FIG. 5 is a fragmentary isometric view of a suction box having airimpermeable members as the suction box cover;

[0030]FIG. 6 is a fragmentary isometric view of a suction box coverhaving air impermeable bars in the nature of circular rods extending inthe machine direction and being spaced apart in the cross direction;

[0031]FIG. 7 is a top plan view of a suction box cover having airimpermeable bars in the nature of flat strips extending longitudinallyin the machine direction and being spaced apart in the cross direction;

[0032]FIG. 8 is a top plan view of the fabric of the invention;

[0033]FIGS. 9A and 9B are top plan views of a pattern screen using arhomboid design and the resultant fabric, respectively;

[0034]FIG. 10A is a fragmentary isometric view of a fabric havingshallow fluid flow highway lanes and thicker fluid flow barrier lanes;

[0035]FIG. 10B is a fragmentary end elevational view of the nonwoven ofFIG. 13A with a spunbond layer of constant thickness applied to eachside thereof;

[0036]FIG. 11 is a fragmentary schematic view of the process for castingan elastic film onto the nonwoven;

[0037]FIG. 12A is a fragmentary isometric view of a nonwoven beinghydroformed by water jet; and

[0038]FIG. 12B is a fragmentary view to an enlarged scale taken alongthe line 12B-12B of FIG. 12A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Referring now to the drawing, and in particular FIG. 1 thereof,therein illustrated is a typical apparatus for making spunbond fabricout of plastic, such as polypropylene. Specifically, polypropylenepellets are processed under heat to a melt in heater 17 and thensupplied to a spinnerette 18. The spinnerette 18 includes an outflowplate 22, with a plurality of holes. The melted polypropylene is forcedthrough the many holes and forms hundreds of thin endless filaments orthreads 20. Air 26 (injected through conduit 24) is used to lengthen thefilaments 20 and thin the diameter of the filaments 20. The filaments 20are then laid down or “collected” on a moving air permeable member, suchas conveyor belt 38 which travels over the suction box cover, and tobond the collected fibers together to form a nonwoven fabric 40. Fabric40 then optionally passes through compaction rollers 42 and 44 and abonding station 48.

[0040] A suction box 32 having a top or cover 32′ is located underconveyor belt 38 and creates a vacuum to pull down the fibers 20 ontothe belt 38 and to keep the air flow 26 moving in the downwarddirection. Accordingly, the conveyor belt 38 is porous or permeable toair, and the suction box top or cover 32′ is also porous or permeable toair. Typically, the top of the prior art suction box (not shown) is asimple metal grating which is uniform in both the machine direction 14(MD) and the cross direction 12 (CD) so that the resulting fabric isalso uniform in both orthogonal directions. Similarly, the prior artbelt (not shown) allows air flow in a uniform manner so that thespunbond filaments will lie flat on the belt in a random, but generallyuniform, manner in both orthogonal directions. Since the air flow causesthe filaments to lie down, any disruption in the air flow (such as alarge spot of dirt on the belt or suction box cover) will result infewer filaments directly above the spot.

[0041] It has now been found that in some instances it would bepreferable to have a non-uniform lay-down of spun fibers (e.g. thespunbond filaments) on the belt in the cross direction. In order toachieve this, in a preferred embodiment a special suction box cover isutilized, which cover is not uniform when comparing the machinedirection to the cross direction. Specifically, the suction box coverincludes a plurality of air impermeable bars which all extend in themachine direction. These bars disrupt the vertical air flow with theresult that the fabric formed on the web will have alternating lanes ofmore fibers and fewer fibers. The bars can be completely air impermeableor substantially air impermeable (e.g. the bars could be formed withsmall holes therein) so long as the bars cause a disruption of the airflow at the point where the fibers are laid onto the moving web. Inessence, the fabric will be striped in the machine direction. Bydisrupting the air flow at the point where the fibers are laid onto themoving web or conveyor belt, lanes having a high density of fibers arejuxtaposed next to lanes having a low density of fibers, all of theselanes running in the machine direction. The end result is a nonwovenfabric 40 which has the expected or standard tensile strength andpercent elongation in the machine direction 14, but decreased tensilestrength and increased percent elongation in the cross direction 12.This is desired where minimal elongation is required in the machinedirection, but high elongation is required in the cross direction.

[0042] Referring now to FIG. 2A in particular, the air permeable member38 serving as the conveyor belt for the collected filaments 40,according to the present invention, may be initially created as apattern of air permeable perforated areas 50 and substantially orrelatively air impermeable non-perforated areas 52 (the non-perforatedareas 52 being designated by white diamonds or parallelograms and theperforated areas 50 being designated by cross-hatching). Thenon-perforated areas 52 are closer together along the MD 14 than alongthe CD 12. Accordingly, the effect of the conveyor belt 38 is to modifythe suction exerted on the falling filaments 20 by the suction box 32 insuch a manner that the filaments 20 will tend to congregate (and therebyassume a higher filament density or weight per unit area) in the MDextending rows formed by the air permeable perforated areas 50 relativeto the CD extending columns formed by the air impermeable imperforateareas 52. The plurality of air permeable areas 50 extend along thelength of the fabric in the MD 14 and are transversely separated fromone another in the CD 12 by the substantially or relatively airimpermeable members 52 extending in the MD 14. Accordingly, the effectof the conveyor belt 38 is to modify the suction exerted on the fallingfilaments 20 by the suction box 32 in such a manner that the filaments20 tend to congregate (and thereby assume a higher filamentconcentration), thus leading to a higher density of the fabric in the MDextending rows formed by the air permeable areas 50 relative to the CDextending columns formed by the substantially or relatively airimpermeable areas 52. It will be appreciated that, as used herein and inclaims, the term “density” is used in terms of weight per unit area(rather than weight per unit volume) and thus is proportional tothickness where the weight per cross-sectional unit is uniform.

[0043] Referring now in particular to FIG. 2B, the conveyor belt 38 isbased upon a generally uniform and symmetrically perforated sheet 54 ofair permeable material to which has been added a series of endlesssubstantially or relatively air impermeable strips or ribbons 56 whichact to block the apertures of the sheet and prevent the passage of airtherethrough. The plurality of ribbons 56 extend along the length of thefabric in the MD 14 and are transversely separated from one another inthe CD 12 by ribbon-like air permeable areas 58 of the air permeableconveyor belt 38 extending in the MD 14. The substantially or relativelyair impermeable areas 58 may be blocked out by applying suitable tapestrips or ribbons 56 to the otherwise uniformly and symmetrically airpermeable conveyor belt 38, such tapes 56 being adhesively or otherwisesecured in place on the conveyor belt 38. The ribbons may be placed oneither side of the belt 38, or formed within the belt.

[0044] Referring now in particular to FIG. 2C, an alternativearrangement is shown wherein the conveyor belt 38 is based upon agenerally uniform and symmetrically perforated sheet 54 of air permeablematerial to which has been added a series of broken or separatedsubstantially or relatively air impermeable strips or ribbons 56′ whichact to block the apertures of the sheet and prevent the passage of airtherethrough.

[0045] As will be obvious to those skilled in the art, differentpatterns than diamonds (FIG. 2A) or endless or broken ribbons (FIGS. 2Band 2C) may be used to define the substantially or relatively airimpermeable portions of the air permeable member. The width of thediamonds or ribbons will determine the width of the strips ofalternating high and low fiber density lanes in the resulting fabric.This in turn will determine the amount of elongation in the CD versusMD. Wider lanes of low density and narrower lanes of high density (allextending in the fabric MD) will result in increased elongation anddecreased tensile in the CD as compared to the MD. It will beappreciated that the conveyor belts illustrated in FIGS. 2A, 2B and 2Care the functional equivalent of a laminate of a uniformly andsymmetrically air permeable conveyor belt and a pattern screen definingsubstantially or relatively air impermeable areas.

[0046] Whether the conveyor belt is specially made to provide aparticular pattern of air permeable areas 50 and substantially orrelatively air impermeable areas 52 (as illustrated in FIG. 2A), orwhether an initially regularly and symmetrically apertured conveyor beltis later specially modified by the placement of substantially orrelatively air impermeable ribbons thereon to provide such air permeableareas 58 and substantially or relatively air impermeable areas 56 (asillustrated in FIGS. 2B and 2C), the reliance on a speciallymanufactured or specially modified conveyor belt could havedisadvantages. In particular, the specially formed or specially modifiedconveyor belts are more expensive. Further, changing of a conveyor beltso as to modify the substantially or relatively air impermeable patternimposed thereon is time consuming and results in idle time. The timerequired for pattern changing, and idle time of the apparatus because ofsuch conveyor changing, may be held to a minimum by use of the preferredembodiments of the present invention described hereinbelow.

[0047] Referring now to FIGS. 3-5, therein illustrated are varioussuction boxes 32 which can be used, either with conventional conveyorbelts 38 defining regular and uniform air permeable patterns or withconveyor belts 38 according to the present invention definingnon-regular and non-uniform air permeable patterns. The suction box ofFIG. 3 may be used with staple fibers, meltblown fibers, carded fibersor short cut fibers, but is not well suited for use with endlessspunbond filaments.

[0048] Referring now to FIGS. 3 and 4 in particular, a series ofsubstantially or relatively air impermeable baffle bars 60A extendlongitudinally in the MD and are transversely spaced across the CD.While the baffle bars 60A are illustrated as being V-shaped in crosssection, clearly they may alternatively be flat, triangular shaped, orthe like, so long as they cause fibers 20 to be deposited primarily inthe vertically aligned areas between the baffle bars 60A rather than theareas vertically aligned with the baffle bars 60A. As illustrated inFIG. 3, in connection with staple fibers, meltblown fibers, cardedfibers and short cut fibers, the baffle bars 60A may be supported,spaced above the conveyor belt upper surface, by a suitable frameworksuch as the upstanding walls of a housing 62 which encloses the area ofpotential fiber deposition on the conveyor belt 38 above the suction box32. At least a small amount of such fibers will be carried under suchbaffle bars 60A and thence onto the permeable member 38 by air currentsso that even the low fiber density areas (that is, the band areasvertically aligned with the baffle bars 60A) will contain sufficientfibers so that the fabric 40 formed by the deposited fibers mayeventually be stripped off the conveyor belt 38 in one piece.

[0049] While FIG. 3 illustrates the baffle bars 60A being disposed abovethe conveyor belt 38, FIG. 4 illustrates the baffle bars 60B beingdisposed beneath the conveyor belt 38 and within the suction box 32,preferably slightly below the plane of the suction box cover 32. It iswell within the competence of those skilled in the art to ascertain aproper placement of the baffle bars 60B within the suction box 32 so asto form the desired alternating strips of high-and low fiber densitylanes alternating across the CD. For example, the width of the strips ofalternating high and low fabric density lanes are determined by thewidth of the baffle bars 60A, 60B and 60C and the gap between adjacentbars. Wider baffle bars (and smaller gaps therebetween) will result inwider lanes of low fabric density and narrower lanes of high fabricdensity, yielding an increase in elongation in the CD and a decrease intensile strength in the CD. The width of the strips of alternating highand low fabric density lanes is also determined by the distance of thebaffle bars 60B and 60C from the web 38. For a given baffle bar width,if the bars are moved closer to the web, then the lanes of fabricdensity will be increased in width and the lanes of high fabric densitywill be decreased in width.

[0050] Referring now to FIG. 5 in particular, therein illustrated is asuction box 32 wherein the cover 32′ thereof defines a plurality ofsubstantially or relatively air impermeable baffle bars 60Clongitudinally extending in the MD and transversely spaced in the CD.Conceptually, the suction box cover 32′ is essentially a plane thatextends across the upper edges of the suction box sidewalls 70.Conventionally, a prior art suction box cover 32′ is either completelyopen, so that there is no impediment to air flow therethrough, oruniformly and symmetrically perforate (permeable), so as to not impartany differential in fiber concentration along the MD and CD directions.However, in a preferred embodiment according to the present invention,as illustrated in FIG. 5, the suction box cover 32′ defines anon-uniform and non-symmetrical pattern of substantially or relativelyair impermeable baffle bars 60C and thus acts to influence the densityof filament deposition on the conveyor belt 38 passing thereover. Whilethe baffle bars 60C are illustrated in FIG. 6 as being of rectangularcross section, clearly they could be of triangular cross section (likethe baffle bars of FIGS. 3 and 4), circular, etc.

[0051] The baffle bars of FIGS. 3-5 may be easily and rapidly changed soas to minimize downtime of the suction box and related apparatus and, atthe same time, avoid the time consumption and expense associated with aneed to change the actual conveyor belt.

[0052] Accordingly, whether the substantially or relatively airimpermeable pattern screen is disposed below the suction box cover(i.e., bars 60B within the suction box, as in FIG. 4), in the plane ofthe suction box cover (bars 60C, as in FIG. 5), or between the suctionbox 32′ cover and the air permeable member 38 (i.e., bars 60A above thesuction box, as in FIG. 3), or is an initial or added air impermeablepart of the air permeable member 38 (i.e., areas 52 or strips 56, as inFIGS. 2A and 2B, respectively), in effect the pattern screen definessubstantially or relatively air impermeable regions (longitudinallyextending in the MD and transversely spaced in the CD) which disrupt theair flow directly above the air permeable member and cause the fabric tohave strips of relatively high fiber density and strips of relativelylow fiber density, the strips extending along the length of the fabricin the MD direction in an alternating pattern across the CD. The highdensity strips are separated from each other by low density strips, thealternating high density and low density strips providing the fabricwith a higher percent elongation and lower tensile strength in the CDthan in the MD. While the pattern screen is positioned in relation tothe air permeable member and the suction box, the optimum positioningthereof for any given application may be determined by routineexperimentation, as discussed above.

[0053] Referring now to FIGS. 6 and 7 in particular, therein illustratedare preferred embodiments of the suction box cover 32′ of the presentinvention similar to FIG. 5 (wherein the substantially or relatively airimpermeable baffle bars 60C are disposed in the plane of the suction boxcover 32′). FIG. 6 illustrates the baffle bars as circular rods 60D, andFIG. 7 illustrates the baffle bars as flat strips 60E. In bothinstances, the substantially or relatively air impermeable bars 60D, 60Eextend axially or longitudinally in the MD 14 and are spaced apart inthe CD 12.

[0054] As illustrated, the baffle bars 60D, 60E are journaled into thesuction box cover 32′ at their ends. While the suction box cover 32′ maybe air permeable throughout, as illustrated the sides of the suction boxcover into which the baffle bars 60D, 60E are journaled may be formed ofa solid, air impermeable material or of a material with a restricted airflow, while the rest of the suction box cover 32′ underneath the bars isuniformly and regularly unrestricted air permeable. The baffle bars maybe rotatable or fixed relative to the suction box cover 32′. By way ofexample, the diameter (width) of the baffle bars 60D (shown in FIG. 6)are 10 mm and the gap between adjacent bars is also 10 mm. Similarly,the width of the baffle bars 60E (shown in FIG. 7) are 10 mm and the gapbetween adjacent bars is also 10 mm. The web travels directly above thebars so the distance between the bars and the web is effectively zero.This arrangement will typically result in a fabric having lanes of highdensity approximately 13 mm in width and lanes of low densityapproximately 7 mm in width. The ratio of weight of the high densitylanes to the low density lanes is preferably in the range of 70 to 85%for the high density lanes versus 30 to 15% for the low density lanes,although ranges of 55 to 95% for high density and 45 to 5% for lowdensity are possible.

[0055] Utilizing the arrangement shown in FIGS. 6 and 7, nonwovenfabrics of 10 and 15 gsm (grams per square meter) were prepared andtested for both elongation and tensile strength utilizing the EDANA testmethod ERT 20.2-89. The tests yielded the following results: FIG. 7/FIG.6 FIG. 7/FIG. 6 Basis Weight 10 gsm 15 gsm CD tensile N 8.76/9.5115.19/17.06 CD elongation % 62.85/57.64 67.13/60.07 MD tensile N20.28/15.67 33.12/21.18 MD elongation % 47.22/43.13 57.43/45.52

[0056]FIG. 8 is shows the fabric of the invention with the high densitylanes 72 and the low density lanes 74.

[0057] The fabric of the present invention is highly extensible in thefirst direction (CD) as compared to the second direction (MD). Themethod of making the fabric of the invention results in the fibers ofthe fabric being oriented more in the MD than in the CD therebyproviding higher tensile strength in the MD than in the CD. Further, inthe fabric of the invention fewer fibers are bonded together in thestrips of relatively high density than in the strips of relatively lowdensity, thereby providing higher elongation and less tensile in the CDthan in the MD.

[0058] The fabric of the invention provides increased liquid wicking inthe strips of relatively high density and increased liquidstrike-through in the strips of relatively lower density. The fabric canbe used as CD extensible outer cover material for diapers and the like.The fabric of the invention can be made as described above with multiplespinning positions and suction boxes to increase the thickness of theresulting fabric.

[0059] As used herein, “elongation” refers to the percentage elongationof a specimen at the breakpoint, and “tensile” refers to the ultimatetensile strength of a specimen at the breakpoint.

[0060] As will be appreciated by those skilled in the art, in order toeffect changes in both the MD and CD properties, variations in thepreliminary compositions, bonding parameters, and thermodynamicparameters (e.g., the spinning, quenching, cooling and drawingparameters) may be used. Such parameter changes affect both the MD andCD properties. By way of contrast, only the formation of the densitypattern of the present invention minimizes the properties in onedirection, while maximizing the properties in the other direction.

[0061] Once formed, the nonwoven fabric of the present invention istypically subjected to uniform and symmetrical bonding of thesubstantially randomly oriented fibers in both the MD and CD so that anydistinction between the MD and the CD properties arises out of theselective density process of the present invention. However, theselective density process of the present invention may also be appliedto a nonwoven fabric which will be bonded asymmetrically in the MD andthe CD. (See the inventor's co-pending U.S. patent application Ser. No.09/374,825 filed Aug. 13, 1999 and entitled “Nonwoven WithNon-Symmetrical Bonding Configuration.”) Where the selective bondingpattern promotes a greater percent elongation in the CD than in the MD,then the use of non-uniform density of the initial nonwoven fabricmerely enhances the elongation ratio (that is, increases the ratio ofelongation in the CD to elongation in the MD). Where the selectivebonding pattern of the nonwoven fabric promotes a greater percentelongation in the MD than in the CD, then the non-uniform density of thepresent invention must be effective to overcome the initial bias andstill cause the fabric to have a greater percent elongation in the CDthan in the MD.

[0062] A preferred embodiment of the present invention provides a methodof making a nonwoven fabric from spun fibers wherein the density of thefabric varies between strips of relative high density and strips ofrelatively low density, the strips extending along the length of thefabric in the machine direction in an alternating pattern, with the highdensity strips separated from each other by low density strips. Thealternating high density and low density strips across the crossdirection provides the fabric with a higher percent elongation in thecross direction than in the machine direction.

[0063] Referring now to FIGS. 9A and 9B in particular, in an improvedpreferred embodiment of the present invention, the pattern screen 99(e.g., the cover 32′ of the suction box 32) includes a plurality ofelongated fluid permeable regions configured and dimensioned as open orhollow rhomboids 100 elongated in the first or machine direction, asbest seen in FIG. 9A. The open rhomboids 100 in the pattern screen actas empty streets to delineate closed or filled rhomboids 102 which actas solid blocks (surrounded by the streets) to form a uniformdistributed network. In the closed rhomboids 102 there will be adiminished build-up of fibers in the fabric relative to an increasedbuild-up of fibers in the fabric occurring in the open rhomboids 100.The resultant fabric 40 illustrated in FIG. 9B has closed rhomboids 104and open rhomboids 106 (corresponding to the open and closed rhomboids100 and 102, respectively, of the pattern screen 99 illustrated in FIG.9A).

[0064] Where the pattern of the pattern screen 99 is formed by openrhomboids 100 defining the elongated fluid permeable regions, theasymmetric nature of the patterning on the final fabric 40, as best seenin FIG. 9B, is difficult to discern visually relative to a regular anduniform pattern formed by rhombuses (i.e., non-elongated or equilateralparallelograms). The use of circles and ovals instead of rhombuses andrhomboids is more noticeable to viewers, presumably because the eye canmore readily detect a lack of perfect circularity than a minorelongation of a rhombus, but such use is within the scope of the presentinvention. Accordingly, while the elongated figure is describedhereinbelow as a rhomboid or ellipse (or oval), clearly any figureelongated in the MD may be used instead. The main axis of the elongatedfigure should form an angle of less than 45° with the MD. Each of theelongated figures along a given MD axis may have their axes ofelongation parallel to one another or each of an adjacent pair ofelongated figures may have their axis of elongation substantiallytransverse to one another. In either case, the elongation along the MDof the closed elongated figure 102 in the pattern screen 99 ensures adiminished lay down of fibers along the CD (relative to the MD).

[0065] Where the pattern on the pattern screen is formed by rhombuses orcircles, the MD/CD density ratio of the fabric is 1 or unity. Where thepattern is formed by rhomboids (i.e., parallelograms with unequaladjacent sides) or ellipses (or ovals) elongated in the direction of theMD, then the MD/CD density ratio of the fabric will be higher than unityand the CD elongation will be greater than the MD elongation.Conversely, where the pattern is formed by rhomboids or ellipses (orovals) shorter in the direction of the MD (e.g., squat relative to therhombus or circle), then the MD/CD density ratio of the fabric will belower than unity and the CD elongation will be less than the MDelongation. The resulting MD/CD density ratio of the fabric 40 istypically in the range of 1.1-10.0 (preferably 1.5-3.0) to 1.0. It willbe appreciated that, even if a spunbond is not present in the fabric,there will always be a sufficient number of fibers connecting thevarious rhomboids or ellipses to hold the web together.

[0066] The open rhomboids 100 of the pattern screen 99 (FIG. 9A) may beused by themselves in straight or even undulating lines substantiallyaligned with the MD to define the fluid permeable strips of the suctionbox cover, simply because the open rhomboids 100 are elongated in the MDand the closed rhomboids 102 defining the fluid impermeable areas areeither not elongated in the MD or are elongated in the MD less than therhomboids 100 in the fluid permeable strips. Indeed, the closedrhomboids 104 defining the fluid permeable areas of the fabric andcorresponding to the open rhomboids 100 of the pattern screen 99 may berhombuses (that is, open equilateral parallelograms which are notelongated in any direction).

[0067] It will be appreciated that the pattern screen 99 may be a partof the suction box cover 32′ (that is, in the plane of a suction boxcover or below or above the suction box cover), only where it moves withthe conveyer belt 38 relative to the suction box 32. Preferably it is anintegral part of the conveyor belt 38.

[0068] Referring now to FIGS. 10A and 10B in particular, in anotherimproved preferred embodiment of the present invention, the nonwoven 40is preferably a meltblown. The thickness of the meltblown fabric 40varies between strips of relatively high thickness 120 (comparable tothe previously described air impermeable strips 56, 102 in the patternscreen 99) and strips of relatively low thickness 122 (comparable to thepreviously described air permeable strips 58, 100 in the pattern screen99). The strips 120, 122 extend along the length of the fabric in the MDin an alternating pattern with the high thickness strips 120 separatedfrom each other by low thickness strips 122. The alternating highthickness and low thickness strips 120, 122 provide the fabric with alower fluid flow rate in the CD than in the MD. The high thicknessstrips 120 act as fluid flow barriers to CD flow and are separated fromeach other by the low thickness strips 122 which act as fluid flow lanesor highways in the MD. The presence of the fluid flow barriers 120 (thatis, the high thickness strips extending in the MD) provide the fabricwith a lower fluid flow rate in the CD than in the MD. The highthickness strips 120 may be thought of as speed bumps extending alongthe MD. The speed bumps 120 resist the flow of fluid transversethereto(in the CD), while encouraging the flow of fluid parallel thereto(in the MD) along the fluid flow highways 122 and intermediate a pair ofadjacent speed bumps 120. Accordingly, liquid flow will occur initiallyin the MD, and then, only if it overflows the fluid flow barriers 120,in the CD.

[0069] This construction is especially useful when high strikethrough isdesired so that a large quantity of fluids may be rapidly spread outalong the MD of the fabric, as may be necessary in a diaper, catamenialpad, or like device subject to liquid flushes. The degree ofstrikethrough is related to the density of the various lanes (lowthickness lanes 122 being characterized by a lower density, and highthickness lanes 120 being characterized by a higher density), how longthe liquid remains in contact with the different lanes (longer for thelow thickness lanes and shorter for the high thickness lanes), etc.Careful selection of the relative thicknesses of the various parallellanes enables the manufacturer to provide a desired dispersal patternfor even massive impacts of liquid L on the fabric (as in a “flush” orburst of urine or blood). The thickness differential is 10-90%,preferably 25-75%, of the speed bump 120.

[0070] The meltblown nonwoven (MB) defining the parallel lanes may beused by itself, as illustrated in FIG. 10A, or in combination with aspunbond nonwoven (SB) 124 on one side or a spunbond nonwoven 124, 124on each side (that is, in an SM or SMS material), as illustrated in FIG.10B. Indeed, one outer surface of the SM or SMS material may be coveredwith an outer layer to provide smoothness where this is desirable (forexample, in an acquisition layer or a topsheet). Assuming that thespunbond 124 is applied at a constant thickness to a meltblown 40 ofundulating thickness, the laminate 126 of the spunbond(s) and themeltblown exhibits a higher liquid strikethrough in the low thickness orhighway lanes 122 (since there is less meltblown there), and a lesserliquid strikethrough in the high thickness or barrier lanes 120 (sincethere is more meltblown there). Alternatively, the spunbond or othernonwoven material 124 may be applied to the meltblown material 40 in anundulating thickness corresponding, for example, to the undulatingthickness of the meltblown material 40. Thus the lanes of low thickness122 and high thickness 120 may be found in the spunbond or othernonwoven material 124 just as in the meltblown material 40. Othernonwoven material, such as nonwoven staple fibers (i.e., fibers oflimited length), may replace the spunbond.

[0071] This material has special utility in diapers, catamenial pads andlike absorbent hygiene products as a core wrap material or a fluiddistribution and wicking layer. If necessary, the material may bereinforced for this purpose by bonding a core wrap material (accordingto the present invention) with an initially separate fluid distributionand wicking layer or by using both a core wrap material layer (accordingto the present invention) and a fluid distribution and wicking layer.

[0072] Referring now to FIG. 11 in particular, in another improvedpreferred embodiment of the present invention, composites or laminates140 are provided of one of the above-described nonwoven fabrics 40 andan elastic film 142.

[0073] Disposable absorbent articles typically contain a number ofdifferent functional layers of nonwovens or composites of nonwovens andelastic film-forming polymers. Each of these layers has to meet specificrequirements as to their properties since they are under stress, tensionand deformation conditions during converting on the assembly ormanufacturing line as well as during later use. The fibrous nonwovensprovide strength to the composite as well as a soft, textile, dryfeeling to at least one of the surfaces of the composite. The elasticpolymer film gives certain elasticity and recovery characteristics afterdeformations both during converting and during later use of theabsorbent article incorporating the same. A breathable elastic polymerfilm further gives a liquid (water) impermeability and a gas (watervapor) permeability. The problem is that the useful combinations ofnonwovens and elastic films are limited to those with physical (i.e.,mechanical) characteristics which are similar or at least comparable;otherwise, the structure of the composite would fracture or delaminateunder stress conditions during converting or use—that is, would sufferbreaking of the bonding points between the film and the nonwoven orcreation of loose or broken filaments in the nonwoven.

[0074] In this process modification, an elastic film 142 is coated ontoa nonwoven 40 according to the present invention, preferably using acast film production method (i.e., direct extrusion of a moltenfilm-forming elastic polymer 142 from a die 144 onto the fabric 40). Incasting, the elastic film 142 is applied from a die 144 onto thenonwoven 40, the composite 140 then passing between a nip roll 146 and achill roll 148 (to cool the film) before removal of the cooled compositefrom the chill roll 148 by a peel roll 150. The cast film has amolecular orientation in the MD. Casting of the elastic film 142directly onto the nonwoven 40 is preferable to each being separatelyformed and then glued or otherwise adhered together as a laminate as itavoids the danger inherent in the use of glue (which may seal the poresrequired for breathability of the composite).

[0075] The elastic film/nonwoven composite 140 according to the presentinvention responds at least to limited CD deformations without a failurein either of the components thereof and without delamination of theelastic film and nonwoven composite. The composite 140 exhibits impactresistance capabilities to allow high impact microdeformations to occurwithout failures or fractures.

[0076] The elastic film/nonwoven composites 140 of the present inventionare particularly suited for use in a variety of industrial application(such as house wrapping, surface protection/low friction layers,packaging, furniture and bedding, car covers and shoe components), avariety of hygiene applications (such as back sheet/outer covers,wastebands, stretch pants and elastic or extensible side bands), and avariety of medical application (such as surgical drapes, surgical gowns,cut-in-place gowns and sterilization wrappings).

[0077] Where the composite 140 has a low CD tensile strength, high CDelongation, and low deformation energy consumption, it may be used as achassis material for disposable diapers and catamenials or as “stretchtabs” for the closure systems or “side panels” of diapers. Where thefilm 142 is liquid impermeable and vapor permeable, the composite 140may be used as a back sheet material for disposable diapers and femininehygiene products (such as catamenials). The resultant composite may bestretched to create breathability.

[0078] Typical elastic films 142 include the thermoplastic elastomerssuch as polyurethane, KRATON, silicone, the polyolefin polymers, and thelike.

[0079] It will be appreciated that, whether or not the cast filmproduction method is used, the coating of an elastic film 142 onto anonwoven 40 according to the present invention strongly reduces breakageof the bonding points between the film and the nonwoven or the creationof loose or broken filaments in the nonwoven so long as stretchingthereof occurs in the CD. This is because the material of the presentinvention exhibits an enhanced CD elongation so that it is able toextend in the CD along with the elastic film. Because the nonwovens ofthe present invention have a reduced elongation in the MD, stretching ofa biaxially elastic film in the MD can still cause the breakage of thebonding points or loose or broken filaments in the nonwoven. However, asnoted earlier, a high percent elongation in the CD is highly desirablein the diaper art, while a high percent elongation in the MD is not.

[0080] Referring now to FIG. 12A in particular, in another improvedpreferred embodiment the process modification is the use, downstream ofweb formation, of jets 160 of a liquid fluid 162 (such as water) to forma post-web formation flowing stream of moveable spun fibers 20 (from theweb) and a liquid 162 with the liquid 162 eventually being received in aliquid discharge box 164 (a form of suction box which operates onliquids much as a suction box 32 operates on gases, discharging theliquid, e.g., for recirculation). The jets 160 act as needles to tanglethe still moveable fibers 20 of the nonwoven 40. The jets 160 do notcreate perforations in the nonwoven 40, but merely create lanes ofhigher and lower density, so that the resultant fabric is unapertured.

[0081] The pattern screen 99′ used in this post-web formation operationis similar to that used in the web formation operation. It is passedbetween the water jets 160 and the liquid discharge box 164. The fluidpermeable member 38 is necessarily liquid permeable for use herein.

[0082] The flowing stream of spun fibers 20 and liquid 162 formed afterweb formation behaves much like the flowing stream of spun fibers 20 andfluid 26 during web formation. As best seen in FIG. 12B, the flowingstream encourages a relatively greater buildup of the spun fibers 20along the travel path of the stream through the pattern screen 99′ and arelatively lesser buildup of the spun fibers 20 where passage of thestream through the pattern screen 99′ is blocked. Because the liquid 162is typically of a higher density and a greater viscosity than the fluid26, it more easily redirects the fibers in the flowing stream so that agreater concentration of fibers is eventually achieved in the desiredhigh density areas and a lesser density of fibers is achieved in thedesired low density areas. Typically the water jets create lanes ofhigher and lower density than can a like number of air jets, but thedividing line between the higher and lower density lanes is coarser whenwater jets are used rather than air jets. The price paid for theenhanced redirection of the spun fibers by the liquid is the additionalexpense involved in circulating (and possibly recirculating) a moredense and more viscous liquid medium 162 (rather than a gaseous medium26). The presence of liquid jets along the MD plays only a minor role,however, compared to the design of the first pattern screen 99 indefining the high and low density strips.

[0083] The liquid 162 used must be relatively pure, must besubstantially incompressible, and must be applied at relatively highpressure in order to effect water “entangling” or “spunlace” formationwithout production problems. For example, de-mineralized water underhigh pressure is directed by jets onto an unbonded web. The fibers andthe filaments get entangled and form a very dense fine structure whichprovides the necessary strength to the web.

[0084] The liquid jets 160 are preferably provided by a wale jet 168extending across the CD of the nonwoven, and optimally by a series ofparallel wale jets 168 being provided at spaced intervals along the MDdownstream of web formation. To avoid the formation of apertures in thefabric, the several wale jets 168 should be staggered across the CD sothat the liquid jets 160 emerging therefrom do not repeatedly hit thesame spot on the fabric and thereby create an aperture rather than thedesired variation of density. Where the number of jets 160 in the MDexceeds the number of jets 160 in the CD, a high extensibility and lowtensile strength in the CD results. Thus, the wale jets 168 preferablyhave a short hole-to-hole separation in the MD, relative to a longhole-to-hole separation in the CD, thereby to provide high extensibilityand low tensile strength in the CD relative to a low extensibility andhigh tensile strength in the MD.

[0085] It is, of course, necessary to keep the fibers 20 of the fabric40 “moveable” after web formation on the conveyor (by the air stream 26)and, therefore, the web can only be slightly “pre-bonded” before itpasses through the water liquid jets 160 which enhance the lanes ofdifferent density along the MD.

[0086] The liquid jet system has the additional advantage of being ableto split bicomponent fibers—for example, a side-by-side polyester (PET)and polyamide (N)—into monocomponent microfibers and, at the same time,entangle them.

[0087] Clearly, two or more of the process modifications describedhereinabove may be combined in the formation of a fabric according tothe present invention—for example, the closed areas of the patternscreen (e.g., the suction or discharge box cover) may be rhomboids, aliquid may be used to further redirect the loose web fibers after webformation, the strips extending along the length of the fabric in the MDin an alternating pattern may be of varying thicknesses in order toprovide liquid flow barriers and liquid flow lanes, and the fabricproduced may be a composite of a nonwoven and an elastic polymer film.

[0088] As used herein, the term “fiber density pattern” refers to thedensity pattern of the fabric or the strips of fabric thereof, and notto the density of the various spun fibers.

[0089] While several embodiments have been described hereinabove asbeing made with air as the fluid used adjacent the spinnerette 18 (inorder the lengthen and thin the filaments 20), in fact other gases andeven other fluids may be used (the term “fluid” encompassing both gasessuch as air and liquids such as water). Typically the fluid systemsdescribed herein will be air flow systems, and the liquid flow systemswill be water flow systems.

[0090] The materials of the present invention find utility in a widevariety of industrial applications. For example, the materials areuseful as filters for air filtration, car filters, liquid filters andfilter bags. The materials are also useful in industrial protectiveclothing such as clean room apparel, commodity consumer clothing, dustprotection and chemical protection. The materials are further useful asindustrial wipes such as clean room wipes, oil absorption wipes, lenscleaning wipes, and surface protection for low friction and/ornon-scratch surfaces. Other industrial applications for the materialsinclude house wrapping, packaging, furniture and bedding, car covers,insulation, battery separators, shoe components and the like.

[0091] Further, the materials of the present invention find utility in awide variety of hygiene applications. For example, the materials areuseful as topsheets, backsheets or outer covers, leg cuffs, waistbands,stretch tabs, elastic or extendable side panels, and acquisition ordistribution layers.

[0092] Finally, the materials of the present invention also find utilityin a wide variety of medical applications. For example, the materialsare useful as surgical drapes, surgical gowns, cut-in-place gowns, shoecovers, bouffant caps and sterilization wrapping.

[0093] The specification of particular applications hereinabove is to betaken as exemplary only, and not as limiting. Uses other than theaforenoted industrial, hygiene and medical applications follow naturallyfrom the physical and chemical properties of the materials of thepresent invention.

[0094] The high CD elongation materials of the present invention findparticular utility in hygienic applications, especially as topsheets,backsheets or outer covers, stretch tabs, elastic or extendable sidepanels and acquisition or distribution layers.

[0095] To summarize, the present invention provides a nonwoven fabrichaving low tensile and high elongation in the first direction (typicallythe CD) and high tensile and low elongation in the second direction(typically the MD) and a method of manufacturing same.

[0096] Fabrics which are pneumatically treated (i.e., treated with gas)or pneumatically and hydrodynamically treated (i.e., treated with gasand liquid) find particular utility in industrial applications (such assurface protection/low friction layers, packaging, furniture andbedding, car covers and shoe components) as well as hygiene applications(such as top sheets, acquisition/distribution layers, and core wraps).

[0097] Now that the preferred embodiments of the present invention havebeen shown and described in detail, various modifications andimprovements thereon will become readily apparent to those skilled inthe art. Accordingly, the spirit and scope of the present invention isto be construed broadly and limited only by the appended claims, and notby the foregoing specification.

We claim:
 1. A method of making a nonwoven fabric from spun fiberswherein the density of the fabric varies between strips of relativelyhigh density and strips of relatively low density, the strips extendingalong the length of the fabric in a first direction in an alternatingpattern, with the high density strips separated from each other by lowdensity strips, the alternating high density and low density stripsproviding the fabric with a higher percent elongation in a seconddirection than in the first direction, comprising the steps of: (A)forming a flowing stream of spun fibers and a fluid; (B) moving a fluidpermeable member over a suction box and across the path of the fiberstream to intercept and collect the fibers on one face of the fluidpermeable member and to bond the collected fibers together to form anonwoven fabric; (C) providing a pattern screen, the pattern screendefining a plurality of elongated fluid permeable regions separated byelongated relatively fluid impermeable regions, the elongated regionsextending in the first direction in an alternating pattern, with thefluid permeable regions separated from each other by the relativelyfluid impermeable regions; (D) positioning the pattern screen inrelation to the fluid permeable member and the suction box to cause thefibers to be collected on the one face of the fluid permeable member soas to form a fabric having a density that varies between strips ofrelatively high density and strips of relatively low density, the stripsextending along the length of the fabric in the first direction in analternating pattern, with the high density strips separated from eachother by low density strips, the alternating high density and lowdensity strips providing the fabric with a higher percent elongation inthe second direction than in the first direction, and the stripsdefining closed rhomboids.
 2. The method of claim 1 wherein liquid jetsare directed against the collected fibers of the web to form a flowingstream of spun fibers and a liquid, and the fluid permeable member isalso moved over a liquid discharge box.
 3. The method of claim 1 whereinthe high density strips are of high thickness and act as fluid flowbarriers and the low density strips are of low thickness and act asfluid flow lanes.
 4. The method of claim 1 including the steps ofcoating an elastic polymeric film onto the fabric along the firstdirection, and separating the collected fibers and cast elastic filmfrom the fluid permeable member.
 5. The method of claim 1 wherein thefabric has an MD/CD density ratio of 1.1-10.0 to 1.0.
 6. The method ofclaim 1 wherein the fabric has an MD/CD density ratio of 1.5-3.0 to 1.0.7. A method of making a nonwoven fabric from spun fibers wherein thedensity of the fabric varies between strips of relatively high densityand strips of relatively low density, the strips extending along thelength of the fabric in a first direction in an alternating pattern,with the high density strips separated from each other by low densitystrips, the alternating high density and low density strips providingthe fabric with a higher percent elongation in a second direction thanin the first direction, comprising the steps of: (A) forming a flowingstream of spun fibers and a fluid; (B) moving a fluid permeable memberover a suction box and across the path of the fiber stream to interceptand collect the fibers on one face of the fluid permeable member and tobond the collected fibers together to form a nonwoven fabric; (C)providing a first pattern screen, the first pattern screen defining aplurality of elongated fluid permeable regions separated by elongatedrelatively fluid impermeable regions, the elongated regions extending inthe first direction in an alternating pattern, with the fluid permeableregions separated from each other by the relatively fluid impermeableregions; (D) positioning the first pattern screen in relation to thefluid permeable member and the suction box to cause the fibers to becollected on the one face of the fluid permeable member so as to form afabric having a density that varies between strips of relatively highdensity and strips of relatively low density, the strips extending alongthe length of the fabric in the first direction in an alternatingpattern, with the high density strips separated from each other by lowdensity strips, the alternating high density and low density stripsproviding the fabric with a higher percent elongation in the seconddirection than in the first direction; (E) providing a second patternscreen, the second pattern screen defining a plurality of elongatedliquid permeable regions separated by elongated relatively liquidimpermeable regions, the elongated regions extending in the firstdirection in an alternating pattern, with the liquid permeable regionsseparated from each other by the relatively liquid impermeable regions;(F) positioning the second pattern screen in relation to the fluidpermeable member and a liquid discharge box to cause the loose fibers tobe collected on the one face of the fluid permeable member so as to forma fabric having a density that varies between strips of relatively highdensity and strips of relatively low density, the strips extending alongthe length of the fabric in the first direction in an alternatingpattern, with the high density strips separated from each other by lowdensity strips, the alternating high density and low density stripsproviding the fabric with a higher percent elongation in the seconddirection than in the first direction; (G) moving the fluid permeablemember and the collected fibers supported thereon over the liquiddischarge box and under the second pattern screen in order to form aflowing stream of loose spun fibers and a liquid; and (H) separating thecollected fibers from the fluid permeable member.
 8. The method of claim7 wherein the elongated fluid permeable regions are configured anddimensioned as rhomboids elongated in the first direction.
 9. The methodof claim 7 wherein the high density strips are of high thickness and actas fluid flow barriers, and the low density strips are of low thicknessand act as fluid flow lanes.
 10. The method of claim 7 including thesteps of coating an elastic polymeric film onto the fabric along thefirst direction, and separating the collected fibers and cast elasticfilm from the fluid permeable member.
 11. The method of claim 7 whereinthe liquid is water.
 12. A method of making a nonwoven fabric from spunfibers wherein the thickness of the fabric varies between strips ofrelatively high thickness and strips of relatively low thickness, thestrips extending along the length of the fabric in a first direction inan alternating pattern, with the high thickness strips separated fromeach other by low thickness strips, the alternating high thickness andlow thickness strips providing the fabric with a lower fluid flow ratein a second direction than in the first direction, comprising the stepsof: (A) forming a flowing stream of spun fibers and a fluid; (B) movinga fluid permeable member over a suction box and across the path of thefiber stream to intercept and collect the fibers on one face of thefluid permeable member and to bond the collected fibers together to forma nonwoven fabric; (C) providing a pattern screen, the pattern screendefining a plurality of elongated fluid permeable regions separated byelongated relatively fluid impermeable regions, the elongated regionsextending in the first direction in an alternating pattern, with thefluid permeable regions separated from each other by the relativelyfluid impermeable regions; (D) positioning the pattern screen inrelation to the fluid permeable member and the fluid discharge box tocause the fibers to be collected on the one face of the fluid permeablemember so as to form a fabric having a thickness that varies betweenstrips of relatively high thickness and strips of relatively lowthickness, the strips extending along the length of the fabric in thefirst direction in an alternating pattern, with the high thicknessstrips acting as fluid flow barriers separated from each other by lowthickness strips acting as fluid flow lanes, the alternating highthickness and low thickness strips providing the fabric with a lowerfluid flow rate in the second direction than in the first direction; and(E) separating the collected fibers from the fluid permeable member. 13.The method of claim 12 wherein the elongated fluid permeable regions areconfigured and dimensioned as rhomboids elongated in the firstdirection.
 14. The method of claim 12 wherein liquid jets are directedagainst the fibers to form a flowing stream of spun fibers and a liquid,and the fluid permeable member is also moved over a liquid dischargebox.
 15. The method of claim 12 including the steps of coating anelastic polymeric film onto the fabric along the first direction, andseparating the collected fibers and cast elastic film from the fluidpermeable member.
 16. The method of claim 12 wherein the thickness ofthe low thickness strips is 10-90% of the thickness of the highthickness strips.
 17. The method of claim 12 wherein the thickness ofthe low thickness strips is 25-75% of the thickness of the highthickness strips.
 18. A method of making a nonwoven fabric from spunfibers wherein the density of the fabric varies between strips ofrelatively high density and strips of relatively low density, the stripsextending along the length of the fabric in a first direction in analternating pattern, with the high density strips separated from eachother by low density strips, the alternating high density and lowdensity strips providing the fabric with a higher percent elongation ina second direction than in the first direction, comprising the steps of:(A) forming a flowing stream of spun fibers and a fluid; (B) moving afluid permeable member over a suction box and across the path of thefiber stream to intercept and collect the fibers on one face of thefluid permeable member and to bond the collected fibers together to forma nonwoven fabric; (C) providing a pattern screen, the pattern screendefining a plurality of elongated fluid permeable regions separated byelongated relatively fluid impermeable regions, the elongated regionsextending in the first direction in an alternating pattern, with thefluid permeable regions separated from each other by the relativelyfluid impermeable regions; (D) positioning the pattern screen inrelation to the fluid permeable member and the suction box to cause thefibers to be collected on the one face of the fluid permeable member soas to form a fabric having a density that varies between strips ofrelatively high density and strips of relatively low density, the stripsextending along the length of the fabric in the first direction in analternating pattern, with the high density strips separated from eachother by low density strips, the alternating high density and lowdensity strips providing the fabric with a higher percent elongation inthe second direction than in the first direction; (E) coating an elasticpolymeric film onto the fabric along the first direction; and (F)separating the collected fibers and elastic film from the fluidpermeable member.
 19. The method of claim 18 wherein the elongated fluidpermeable regions are configured and dimensioned as rhomboids elongatedin the first direction.
 20. The method of claim 18 wherein liquid jetsare directed against the collected fibers of the web to form a flowingstream of spun fibers and a liquid, and the fluid permeable member isalso moved over a liquid discharge box.
 21. The method of claim 18wherein the high density strips are of high thickness and act as fluidflow barriers and the low density strips are of low thickness and act asfluid flow lanes.
 22. The method of claim 18 wherein the elasticpolymeric film is cast coated onto the fabric.
 23. A method of making anonwoven fabric from spun fibers wherein the density and thickness ofthe fabric varies between strips of relatively high density andthickness and strips of relatively low density and thickness, the stripsextending along the length of the fabric in a first direction in analternating pattern, with the high density and thickness stripsseparated from each other by low density and thickness strips, thealternating high density and thickness and low density and thicknessstrips providing the fabric with a higher percent elongation and lowerfluid flow rate in a second direction than in the first direction,comprising the steps of: (A) forming a flowing stream of spun fibers anda fluid; (B) moving a fluid permeable member over a suction box andacross the path of the fiber stream to intercept and collect the fiberson one face of the fluid permeable member and to bond the collectedfibers together to form a nonwoven fabric; (C) providing a patternscreen, the pattern screen defining a plurality of elongated fluidpermeable regions separated by elongated relatively fluid impermeableregions, the elongated regions extending in the first direction in analternating pattern, with the fluid permeable regions separated fromeach other by the relatively fluid impermeable regions, the elongatedfluid impermeable regions being configured and dimensioned as rhomboidselongated in the first direction; (D) positioning the pattern screen inrelation to the fluid permeable member and the suction box to cause thefibers to be collected on the one face of the fluid permeable member soas to form a fabric having a density and thickness that varies betweenstrips of relatively high density and thickness and strips of relativelylow density and thickness, the strips extending along the length of thefabric in the first direction in an alternating pattern, with the highdensity and thickness strips acting as fluid flow barriers separatedfrom each other by low density and thickness strips acting as fluid flowlanes, the alternating high density and thickness and low density andthickness strips providing the fabric with a higher percent elongationand lower fluid flow rate in the second direction than in the firstdirection; (E) coating an elastic polymeric film onto the fabric alongthe first direction; and (F) separating the collected fibers and castelastic film from the fluid permeable member.
 24. A nonwoven fabric fromspun fibers formed into a single sheet wherein the density and thicknessof the spun fibers in the fabric varies between strips of relativelyhigh density and thickness and strips of relatively low density, thestrips extending along the length of the fabric in the machine directionin an alternating pattern with the high density and thickness stripsseparated from each other by low density and thickness strips, thealternately high density and thickness and low density and thicknessstrips providing the fabric with a higher percent elongation and a lowerliquid flow rate in the cross direction than in the machine direction.25. A nonwoven fabric made from spun fibers wherein the density of thefabric varies between strips of relatively high density and strips ofrelatively low density, the high/low density ratio being 1.1-10.0 to1.0, the strips extending along the length of the fabric in a firstdirection in an alternating pattern, with the high density stripsseparated from each other by low density strips, the alternating highdensity and low density strips providing the fabric with a higherpercent elongation in a second direction than in the first direction,the strips defining closed phomboids elongated in the second direction.26. The fabric of claim 25 wherein the density ratio is 1.5-3.0 to 1.0.27. A nonwoven fabric made from spun fibers wherein the density of thefabric varies between strips of relatively high density and strips ofrelatively low density, the strips extending along the length of thefabric in a first direction in an alternating pattern, with the highdensity strips separated from each other by low density strips, thealternating high density and low density strips providing the fabricwith a higher percent elongation in a second direction than in the firstdirection, the strips being initially formed by selective fluid flow andthen at least partially re-formed by selective liquid flow.
 28. Thefabric of claim 27 wherein the liquid flow is water flow.
 29. A nonwovenfabric made from spun fibers wherein the thickness of the fabric variesbetween strips of relatively high thickness and strips of relatively lowthickness, the strips extending along the length of the fabric in afirst direction in an alternating pattern, with the high thicknessstrips separated from each other by low thickness strips, the highthickness strips acting as fluid flow barriers separated from each otherby low thickness strips acting as fluid flow lanes, the alternating highthickness and low thickness strips providing the fabric with a lowerfluid flow rate in a second direction than in the first direction. 30.The fabric of claim 29 wherein the thickness of the low thickness stripsis 10-90% of the thickness of the high thickness strips.
 31. The fabricof claim 29 wherein the thickness of the low thickness strips is 25-75%of the thickness of the high thickness strips.
 32. A laminate of (A) anonwoven fabric made from spun fibers wherein the density of the fabricvaries between strips of relatively high density and strips ofrelatively low density, the strips extending along the length of thefabric in a first direction in an alternating pattern, with the highdensity strips separated from each other by low density strips, thealternating high density and low density strips providing the fabricwith a higher percent elongation in a second direction than in the firstdirection; and (B) an elastic polymeric film coated onto the fabricalong the first direction.
 33. The laminate of claim 32 wherein theelastic polymeric film is cast coated onto the fabric.